Book rough cutter with raker tooth

ABSTRACT

A cutting wheel for roughing the backbone of the collated leaves in an unbound book has a number of rough cutting teeth set around the periphery of a disk or like wheel body, each tooth having a cutting edge formed by a leading surface which is inclined radially inwardly and rearwardly with respect to disk rotation so that as the book is fed into the wheel each tooth cuts and partially detaches a series of tab like fragments along the backbone edge of each leaf and then twists the tabs with a tearing action. One or more raker teeth with raking edges slightly below the ends of the cutting teeth edges inclined oppositely to the cutting teeth twist the tabs with reverse twist tearing them from the leaves so as to leave a substantially continuous fibrous edge along the torn edge of the leaves.

' [22] Filed:

Unite ll? Aspinwall States Patent 1 BOOK ROUGH CUTTER WITH RAKER TOOTH [75] Inventor: Peter Aspinwall, Carlisle, Mass.

[73] Assignee: Comstock & Wescott, Inc.,

Cambridge, Mass.

June 4, 1973 21 Appl. No.1 366,464

[52] U.S. Cl 225/94, 29/567, 83/837, 83/854 [51] Int. Cl 826d 1/14, B26f 3/02 [58] Field of Search 29/567; 144/218; 83/849, 83/850, 851, 854, 925 A, 837; 225/94, 97

[56] References Cited UNITED STATES PATENTS 3,027,106 3/1962 Brooks 144/218 X 3,706,252 12/1972 Hawkes et al. 83/925 A 3,726,167 4/1973 Barbour, Jr 83/925 A 1 1 Jan. 14, 1975 Primary Examiner-J. M. Mcister Attorney, Agent, or FirmJames H. Grover [57] ABSTRACT A cutting wheel for roughing the backbone of the collated leaves in an unbound book has a number of rough cutting teeth set around the periphery of a disk or like wheel body, each tooth having a cutting edge formed by a leading surface which is inclined radially inwardly and rearwardly with respect to disk rotation so that as the book is fed into the wheel each tooth cuts and partially detaches a series of tab like fragments along the backbone edge of each leaf and then twists the tabs with a tearing action.

One or more raker teeth with raking edges slightly below the ends of the cutting teeth edges inclined oppositely to the cutting teeth twist the tabs with reverse twist tearing them from the leaves so as to leave a substantially continuous fibrous edge along the torn edge of the leaves.

7 Claims, 9 Drawing Figures BOOK ROUGH CUTTER WITH RAKER TOOTH BACKGROUND OF THE INVENTION In the bookbinding art the backbone or hinge edge of the collated pages of an unbound book is rough cut to prepare the backbone for the application of glue. The rough cut is typically made with a rough cutting wheel or rotary saw which leaves a ragged edge on each book leaf at the backbone. Such a ragged edge is a desirable foundation for the binding glue, but often the rough cutting wheel forms small tabs partly attached to the leaf edges at the backbone. The tabs hold glue well, but when the cover is glued to the backbone the tabs have a tendency to separate from the leaves and allow the cover to detach from the book. For this reason it has been considered impractical to rough cut into the backbone more than 0.010 or 0.015 inch because of exces sive tab formation, although deeper cuts are often desirable.

Accordingly the object of the present invention is to provide a book rough cutter which provides improved roughing and exposed fibre formation with rough cuts of up to 0.045 inch depth at the backbone edges of book leaves, but which substantially eliminates the partially detached tabs.

SUMMARY OF THE INVENTION According to the invention a cutting wheel for roughing the backbone of the collated leaves in an unbound book comprises a planar disk rotatable in a given direction; a plurality of cutting teeth spaced around the disk, each tooth including a leading surface with a cutting edge extending transverse the disk plane, the leading surface having a radially inward inclination in one direction with respect to disk rotation so as to twist partially detached paper fragments at the leaf edges in one direction; and atleast one raker tooth on the disk having a raking edge substantially coplanar with one end of the cutting edge, the raker tooth being inclined at an angle deviating oppositely to the radially inward inclination of the leading surface so as to twist the partially detached fragments oppositely to the twist of the leadingsurface and tear the fragments from the book leaves leaving a substantially continuous rough, fibrous edge on the leaves.

DRAWING FIG. 1 is a top plan view of book cutting apparatus, parts beingbroken away;

FIG. 2 is a section on line 22 of FIG. 1;

FIG. 3 is an enlarged side elevation of a portion of a book rough cutting wheel;

FIG. 4 is an enlarged plan view of wheel portion of FIG. 3;

FIG. 5 is an enlarged side elevation like FIG. 3.

FIGS. 6 to 9 are enlarged schematic side elevations showing. the cutting and roughing operations on the backbone of a book.

DESCRIPTION As shown in top plan view of FIG. 1 the collated pages of a book 1 are held between clamps 2 and fed on a line indicated by an arrow 1* past a circular backup plate 3 and over a rougher-raker wheel 4 rotating in the direction of arrow 4*. As is known in the art the back-up plate 3 has a groove 6 on its under side accommodating the cutting wheel while an ungrooved skirt portion 7 holds the exposed backbone at the lower edge of the book against displacement by the wheel. The wheel has a relatively large number, e.g., 44, carbide roughing teeth 8, and one or more carbide raker teeth 9 located above and below the disk shaped body 11 of the wheel.

The roughing teeth 8, as shown enlarged in FIGS. 2 to 5, are set by brazing or welding in triangular sockets 12 in the periphery of the disk body. Each roughing tooth 8 is generally in the shape of a 60 triangular prism 0.75 inches long and 0.25 inches on each side extending transversely above and below the plane of the disk 11. Each tooth has a leading surface 13 with respect to disk rotation 4*. The leading surface has a cutting edge 14 extending between points A and D at the upper side of the disk. The upper end of the roughing tooth is a triangular facet defined by points A, B and C. Line A B is inclined typically 10 from the horizontal with downward clearance in respect to disk rotation. Line A C is typically inclined 30 to 35 inwardly and downwardly of the disk. A small chamfer is ground at the upper, outer corner A of the leading surface 13.

The raker tooth 9 is a simple rectangular bar five eighths of an inch long, 3/8 of an inch wide and one quarter inch thick set in a rectangular socket 21 so that the top surface 22 has a slight clearance Z, e.g., 0.007 inch, below the corners A of the roughing teeth 8. The raker tooth has a leading raking edge 23 bounded by the top surface 22, which raking edge extends to radially outer corner 24 located inwardly of the cutting edges of the roughing teeth 8 approximately at the radius of the disk body 11, but above the plane side of the disk. Whereas the leading surface 13 of the roughing teeth 8 is inclined with positive hook inwardly and rearwardly with respect to disk rotation 4*, the raking edge of the raker teeth 9 is inclined with negative hook inwardly and forwardly, or oppositely to the roughing teeth inclination with respect to disk rotation. Other inclinations of the raker tooth may be used so long as their inclination deviates oppositely with respect to the inclination of the roughing teeth.

In backbone roughing operation the effect of the roughing and raking teeth is shown in FIGS. 6 to 9.

In FIG. 6 a roughing tooth 8 is shown entering the backbone portion 10 of the book 1 which depends below the clamps 2 of FIG. 1. The roughing teeth extend to an upward depth of cut X typically of 0.025 to 0.045 inch, typically 0.035 to 0.045 the out being made by the cutting edge 14 between points A and D. The vertical cut 31 through each leaf of the book is relatively precise and clean.

In FIG. 7 the book has advanced between the penetration of the previous roughing tooth 8 by a distance F of book roughing feed per tooth. With a forty four roughing tooth wheel, 9.25 inch in diameter, rotating at 3,600 rpm, and a linear book feed of 3,000 inches per minute the book feed rate per tooth is 0.017 inch. As shown in FIG. 7 successive vertical cuts 31, 31* are made at the feed rate forming a series of tab or chip shaped fragments 32 along the backbone edge of each book leaf 1. Tab formation may be increased by increasing the book feed rate per tooth. In FIG. 7 two such clean cut tabs are shown as successive roughing teeth 8 make the clean vertical cuts 31 and 31*.

As shown in FIG. 8 each roughing tooth 8, in addition to making the clean vertical cuts 31 of FIG. 7, also tends to twist each tab 32 around a vertical axis Y out of the plane of the leaf 1 and also bends the tab along the plane of its leaf rotating the axis of the tab from position Y to Y*. The axial twisting of the tab indicated by the arrow T -is attributable to the previously described inwardly rearward inclination of the roughing tooth leading surface 13. The bending is due to the rotational advance of the tooth, it being believed that the inclined upper facet of the roughing tooth allows the tab to slide over the top of the tooth after bending. In any event, the twisted and bent condition of the tabs can be observed together with the tearing of the tab at the extreme depth of cut 33 where rough fibres 34 are formed at the edge of the backbone. As previously explained the partially detached tab fragments are undesirable because they will absorb the subsequently applied binding glue joining the backbone to the book cover, but then tear loose from the leaves allowing the leaves to separate from the book.

According to the invention the tabs partially torn from the backbone by the roughing teeth are further torn from the backbone by one or more raker teeth 9. The raker teeth 9 because of their opposite inclination relative to the roughing teeth impart a counter twist T* to the tab 32 completing the tearing of the tab from its leaf 1 and completing formation of a rough fibrous torn edge 34, 35 substantially continuously and free of tabs along the backbone. Such a fibrous edge forms an ideal foundation for glue. The fibre exposure can be increased by increasing the book feed rate per tooth with a consequent increase in tab width to be torn. Tab length may be varied by adjusting the depth of vertical cut by the roughing teeth 8, but the leading edge 23 at the top surface 22 of the raker tooth 9 should have a clearance Z (FIG. 2) such that the leading edge preferably strikes the tab 32 above its center of gravity but below the torn fibres.

It should be understood that the present disclosure is for the purpose of illustration only and that this invention includes all modifications and equivalents which fall within the scope of the appended claims.

I claim:

l. A cutting wheel for roughing the backbone leaf edges of an unbound fibre paper'book comprising:

a planar disk rotatable in a given direction;

a plurality of cutting teeth spaced around the disk,

each tooth including a leading surface with a cutting edge extending transverse the disk plane, the leading surface having a radially inward inclination in one direction with respect to disk rotation so as to twist partially detached paper fragments at the leaf edges in one direction; and

at least one raker tooth on the disk having a raking edge substantially coplanar with one end of the cutting edge, the raker tooth being inclined at an angle deviating oppositely to the radially inward inclination of the leading surface so as to twist the partially detached fragments oppositely to the twist of the leading surface and tear the fragments from the book leaves leaving a substantially continuous rough, fibrous edge on the leaves.

2. A wheel according to claim 1 wherein the raker tooth leading surface is inclined oppositely to the inclination of the rougher tooth leading surface with respect to disk radius.

3. A wheel according to claim 1 wherein the leading surface of each roughing tooth has a positive hook of radially inward inclination rearwardly of the direction of disk rotation, and the raker tooth has a negative hook of radially inward inclination forwardly of the direction of disk rotation.

4. A wheel according to claim 1 wherein the leading surface of the raker tooth extends axially of the disk less than the end of the cutting teeth leading surface.

5. A wheel according to claim 4 wherein the difference in axial extent of the roughing and raking teeth is greater than the torn paper fiber length and less than half the length of the paper fragments.

6. A wheel according to claim 1 wherein each roughing tooth has a facet at its axially outer end, the facet being inclined radially inwardly and downwardly toward the plane of the disk. 7

7. A wheel according to claim 6 wherein the facet has downward clearance with respect to disk rotation. 

1. A cutting wheel for roughing the backbone leaf edges of an unbound fibre paper book comprising: a planar disk rotatable in a given direction; a plurality of cutting teeth spaced around the disk, each tooth including a leading surface with a cutting edge extending transverse the disk plane, the leading surface having a radially inward inclination in one direction with respect to disk rotation so as to twist partially detached paper fragments at the leaf edges in one direction; and at least one raker tooth on the disk having a raking edge substantially coplanar with one end of the cutting edge, the raker tooth being inclined at an angle deviating oppositely to the radially inward inclination of the leading surface so as to twist the partially detached fragments oppositely to the twist of the leading surface and tear the fragments from the book leaves leaving a substantially continuous rough, fibrous edge on the leaves.
 2. A wheel according to claim 1 wherein the raker tooth leading surface is inclined oppositely to the inclination of the rougher tooth leading surface with respect to disk radius.
 3. A wheel according to claim 1 wherein the leading surface of each roughing tooth has a positive hook of radially inward inclination rearwardly of the direction of disk rotation, and the raker tooth has a negative hook of radially inward inclination forwardly of the direction of disk rotation.
 4. A wheel according to claim 1 wherein the leading surface of the raker tooth extends axially of the disk less than the end of the cutting teeth leading surface.
 5. A wheel according to claim 4 wherein the difference in axial extent of the roughing and raking teeth is greater than the torn paper fiber length and less than half the length of the paper fragments.
 6. A wheel according to claim 1 wherein each roughing tooth has a facet at its axially outer end, the facet being inclined radially inwardly and downwardly toward the plane of the disk.
 7. A wheel according to claim 6 wherein the facet has downward clearance with respect to disk rotation. 